Indonesian investigators have revealed the doomed Lion Air plane had a crucial sensor replaced the day before it crashed into the sea killing all 189 people onboard.
Authorities said the “angle of attack” sensor, which helps the aircraft adjust the angle of its nose relative to the current of air to prevent stalling and diving, could have worsened existing problems with the plane.
Flight data retrieved from the aircraft showed airspeed indicator malfunctions on the jet’s last four flights, which Transport safety committee chairman Soerjanto Tjahjono said would have been intertwined with the sensor issue.
“The point is that after the AOA [sensor] is replaced the problem is not solved, but the problem might even increase. Is this fatal? NTSC wants to explore this,” he said, according to the ABC.
Tjahjono said the airline’s first two attempts to fix problems with the sensor failed, so they replaced it on the aircraft’s second-last flight.
During the second-last flight, the plane went into a sudden dive minutes after take-off which the pilots were able to recover from.
Boeing has since provided Lion Air with draft procedure recommendations based on how the flight crew responded to the problems on the second last flight.
Meanwhile, the Civil Aviation Safety Authority has issued an “urgent airworthiness directive” from the Federal Aviation Administration, according to News Corp.
Prompted by Lion Air’s reported issues with the “angle of attack” sensor, the directive said that if this issue isn’t addressed the flight crew could have “difficulty controlling the aeroplane”.
The FFA said the condition is likely to exist or develop in other products of the same type.
“Due to the need to correct an urgent safety of flight situation, good cause exists to make this airworthiness directive effective in less than 30 days,” the directive said.
The doomed jet was a Boeing 737-Max 8 and is one of the world’s newest and most advanced commercial passenger planes.
Human remains are still being recovered as the search continues for the cockpit voice recorder.
The search, which has been extended a second time, is expected to conclude on Sunday.
The flight was on its way from Jakarta to Pangkal Pinang on the island of Bangka when it lost contact with air traffic control 13 minutes after takeoff, and crashed into the sea.
All 189 people on board were killed in what is being called the worst airline disaster in Indonesia in more than 20 years, sparking fresh concerns about the country’s fast-growing aviation industry which was only just removed from EU and US blacklists.